Technical Field
The present disclosure relates to a syringe assembly mounted with a seal cap, a prefilled syringe using the syringe assembly mounted with the seal cap, and a package body storing a plurality of syringe assemblies.
Background Art
A syringe having a puncture needle fixed at a distal end of a barrel is used as a syringe for administering a low dose of medical solution, such as an insulin syringe. When a prefilled syringe in which a medical solution is prefilled is provided using a syringe of this type, the tip of the needle needs to be sealed. Such a seal cap for sealing the tip of a needle is disclosed, for example, in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2010-534546, or WO2011114917 (US2013012886).
A seal cap (shield 10) of JP 2010-534546 is configured to cover the distal tip of a syringe (partially shown on FIG. 2 of JP 2010-534546). The distal tip of the syringe 3 includes a hub 2 on which a needle 6 is fixed. The shield 10 has an open proximal end 11, a closed distal end 12, and a wall 13 extending from the proximal end 11 to the closed distal end 12. The internal face 14 of the wall 13 defines a cavity 15 for receiving the part of the distal tip of the syringe 3. A portion 14a of the internal face 14 is configured to be in contact with the hub 2 of the distal tip of the syringe 3 when the shield 10 is secured on the distal end tip of the syringe in order to protect the distal tip, for example during transport of an administration device before use.
In FIG. 3 of JP 2010-534546, the portion 14a of the internal face 14 of the wall 13 includes a plurality of grooves 16. The grooves 16 are regularly disposed along the circumference of the portion 14a, they are parallel to the longitudinal axes A of the shield 10. They allow air to flow during the assembly of the shield on the hub 2. A sticky surface of the shield is small, so the assembly is facilitated, and it is easy to have the respective longitudinal axis A and B (see JP 2010-534546 FIG. 2) of both the shield 10 and the administration device 3 remain confounded. The shield 10 of the device is therefore perfectly and accurately secured on the tip of the administration device 3. Because of the grooves created by the specific roughness of the portion 14a of the internal face 14 of the wall 13, it is then easier to remove the shield 10 from the tip of the administration device 3 at the time of use of the administration device 3.
In a syringe needle cap 10 of WO2011114917 (US2013012886), the cap is fitted to the tip of a barrel 21 of a prefilled syringe 20, and the tip of a syringe needle 22 is stuck into a needlepoint receiving section 12A on an inner layer portion 12 of the syringe needle cap 10. The outer circumference of a head section 21B on the tip of the prefilled syringe 20 is closely attached to a joining section 12B on the inner layer portion 12 of the syringe needle cap 10, thereby securely sealing the inner space within the syringe needle cap 10 which covers the syringe needle 22. An outer layer portion 11 functioning as the cap main body of the syringe needle cap 10 is formed from a transparent resin, and the inner layer portion 12 is formed from a transparent elastomer as the interior material. As a consequence, the entire syringe needle 22 of the prefilled syringe 20, including the tip section, can be seen from the outside.
In JP 2010-534546, the internal face of the opening of the seal cap (shield 10) has the plurality of grooves axially extending, and the seal cap is readily mounted to and removed from a barrel. However, since the seal cap is readily removed, when the barrel or the prefilled syringe mounted with the shield 10 is manufactured, and when the barrel or the prefilled syringe mounted with the shield 10 is transported, the shield 10 is likely to be removed unexpectedly from the barrel.
The syringe needle cap 10 of WO2011114917 (US2013012886) is configured such that a projection portion on an inner surface of a cap (ring shaped bump 12C) engages only with a ring shaped recessed portion at a barrel end portion (upper circumference of the head section 21B). Therefore, when a pressure difference is generated between the inside and the outside of the cap due to autoclave sterilization or the like, a force larger than an engagement force between the projection portion and the ring shaped recessed portion is likely to be applied to remove the cap.
When a syringe assembly is for example washed, air around the syringe assembly is sucked for removing foreign bodies, and sometimes pressure around the cap is reduced and pressure in the cap is relatively increased. Further, when the syringe assembly is sterilized by a sterilization method using a sterilization gas, such as, autoclave sterilization, ethylene oxide gas sterilization, or hydrogen peroxide gas sterilization, the inside of a sterilization apparatus in which the syringe assembly is put needs to be depressurized before the sterilization gas is introduced into the sterilization apparatus. Therefore, pressure around the cap is reduced and the pressure in the cap is relatively increased. Further, in the autoclave sterilization or the ethylene oxide gas sterilization, it is also considered that pressure in the sterilization apparatus is changed due to variation in air volume caused by temperature change, and pressure in the cap is increased relative to pressure around the cap. As described above, when the pressure in the cap is increased relative to the pressure around the cap, a repulsive force acts between the cap and the distal end of the barrel in a direction to separate the cap and the barrel. The repulsive force facilitates the removal of the cap from the distal end of the barrel.